The FDA has recommended that no new patients with advanced soft tissue sarcoma (STS) should be treated with the combination of olaratumab (Lartruvo) plus doxorubicin, following the negative results of the phase III ANNOUNCE trial.1

The agency's statement follows the January 2019 announcement that olaratumab in combination with doxorubicin missed the ANNOUNCE trial’s primary endpoint of overall survival (OS) and did not confirm a clinical benefit for patients with advanced or metastatic STS compared with standard doxorubicin.2 The OS endpoint in the leiomyosarcoma subpopulation was also not met.

"In light of this information, the FDA recommends that patients who are currently receiving Lartruvo should consult with their healthcare provider about whether to remain on the treatment," the FDA stated in a press release. "The FDA also recommends that Lartruvo should not be initiated in new patients outside of an investigational study."

Additionally, the European Medicines Agency (EMA) issued a similar recommendation based on the negative findings of the confirmatory trial, stating that the combination of olaratumab and doxorubicin should not be administered in any new patients with advanced STS.3

Both the FDA and EMA made statements recommending that patients currently receiving olaratumab may continue to receive the treatment if they appear to be benefitting from it. Approximately 1100 patients in the European Union are currently treated with olaratumab.

Results of ANNOUNCE (NCT02451943), which was the confirmatory trial for the FDA approval of olaratumab in this setting, showed that there was no difference in OS between the 2 arms. The median OS was 20.4 months with olaratumab/doxorubicin and 19.7 months with doxorubicin (HR, 1.05). In the leiomyosarcoma subpopulation, the median OS was 21.6 months and 21.9 months for olaratumab/doxorubicin and doxorubicin, respectively.

Moreover, the median PFS with olaratumab/doxorubicin was 5.4 months and was 6.8 months with doxorubicin alone (HR, 1.23).

Regarding safety, olaratumab was found to be well tolerated and no new safety signals were reported. Eli Lilly and Company, the manufacturer of olaratumab, will present the full findings at an upcoming medical meeting and will be published at a later date.

The company stated in a previous press release that the phase III data do not support starting patients on the therapy outside of a clinical trial.

The double-blind ANNOUNCE trial randomized approximately 460 patients to receive olaratumab in combination with doxorubicin, followed by olaratumab alone, compared with doxorubicin plus placebo followed by placebo in patients with advanced or metastatic STS. Olaratumab was given at a loading dose of 20 mg/kg on days 1 and 8 of cycle 1 and 15 mg/kg on days 1 and 8 of all subsequent cycles, combined with doxorubicin at 75 mg/m2 administered on day 1 of each cycle. Placebo was given in combination with doxorubicin for 8 cycles, while olaratumab was continued as a single agent until disease progression.

To be eligible for enrollment, patients had to have locally advanced, unresectable or metastatic STS not amenable to curative treatment and could have had any prior number of therapies, as long as they did not previously receive an anthracycline. Secondary endpoints of the study were safety, progression-free survival (PFS), objective response rate (ORR), and patient-reported outcomes.

In November 2016, the European Commission approved the PDGFRα antagonist olaratumab in combination with doxorubicin for the treatment of patients with advanced STS who are ineligible for radiotherapy or surgery; this was contingent on the results of a confirmatory trial. The FDA approved olaratumab for the same indication in October 2016.

This approval was based on data from the phase II JGDG study, which demonstrated a 48% reduction in the risk of death with olaratumab and doxorubicin versus doxorubicin alone (HR, 0.52; 95% CI, 0.34-0.79, P <.05).3 In the 133-patient, randomized, US trial, the median OS in the intent-to-treat population (n = 129) was 26.5 months with olaratumab/doxorubicin versus 14.7 months with doxorubicin alone.

Of those enrolled, 129 received at least 1 dose of treatment (64, olaratumab/doxorubicin; 65, doxorubicin).

Patient characteristics were well balanced between the arms. The median age of patients in the combination arm was 58.5 years, and most had an ECOG performance status of 0 to 1 (94%). Additionally, 88% of patients were positive for PDGFRα. Thirty-six percent and 40% of patients had leiomyosarcoma, in the combination and monotherapy arms, respectively. Other common histologies in the olaratumab and control arms, respectively, included undifferentiated pleomorphic sarcoma (15% vs 21%, respectively) and liposarcoma (12% vs 22%).